An example of the electronic musical instrument is disclosed in Japanese Patent Application laid-open (Kokai) No. 58-211191. This prior-art electronic musical instrument has not only an recording mode of operation but also an editing mode of operation. In the recording mode of operation, a sequence of pieces of musical data information are produced in accordance with keying-in operations on a keyboard and memorized in a piece of musical data information memory. When a player shifts the mode of operation from the recording mode to the editing mode, a new sequence of pieces of musical data information are produced and memorized in addition to the pieces of musical data information which have already been memorized in the musical data information memory. The electronic musical instrument thus arranged is capable of overlapping the pieces of musical data informations for a new edition.
However, a problem is encountered in the prior-art electronic musical instrument in modification of a sequence of the pieces of musical data information representative of attributes of musical tones recorded in the musical data information memory. This sets limitations to editing mode of operation.